Pipe wrench

ABSTRACT

A pipe wrench has a holder ring unit (2-2) and a dog actuating ring unit (1-1) which units are coaxial and turnable relative to each other by means of a handle (8, 9). A number of dogs (3) are pivotally mounted on bolts (5) of the holder ring unit and actuated so as to pivot into gripping positions by means of bolts (6) of the dog actuating ring unit when the handle is actuated.

Unlted States Patent 1151 3,698,266

Mader 1451 Oct. 17, 1972 PIPE WRENCH [56] References Cited [72] Inventor: Horst Heinrich Georg Mader, UNITED STATES PATENTS H en g, Ge y 2,516,394 7/1950 Keiser ..8l/5 3.2 e 1,531,377 3/1925 Clarke ..8l/53 R Ass'gnee' ggzz f Ambdag Nackas' 2,744,270 12/1956 Daniel mm A [22] Filed: April 26, 1971 Primary Examiner-James L. Jones, Jr. [211 pp No: 137,306 Attorney-Bauer E. Goodman [57] ABSTRACT [30] Fm'eig Application Priority Data A pipe wrench has a holder ring unit (2--2) and a dog April 28, 1970 Germany ..P 20 20 625.1 actuating ring unit which un ts are coaxial and turnablerelative to each other by means of a handle 52 US. Cl. "81/53 A 81/91 A number (3) are Pivmally mum! Int. Cl. bolts 0f the holder ring unit and actuated So 88 t0 [58] Field of Search 81/53 A 53 2 91 pivot into gripping positions by means of bolts (6) of the dog actuating ring unit when the handle is actuated.

8 Claims, 3 Drawing Figures PATENTEDncI 11 m2 SHEET 3 [1F 3 A PIPE WRENCH This invention relates to a pipe wrench.

When a thin-walled pipe or pipe-like element is to be held firmly, the risk of deforming the pipe is considerable. A core barrel used in core drilling in rocks, for instance, can easily be damaged when the drill bit screwed to its end is being removed. Because of the rotation during drilling in combination with the drilling mud that penetrates into the threads, the threads between the drill bit and the core barrel will adhere and, therefore, a great torque will sometimes be needed for unscrewing. It is desirable that the radial gripping forces exerted by the dogs on the core barrel be great enough to secure the dogs from slipping, but, the maximum gripping power should be avoided when it is not necessary.

It is an object of the invention to provide a simple pipe wrench in which the radial gripping forces always match the torque.

The invention will be described in more detail with reference to the accompanying drawings in which a preferred embodiment of the invention is described.

In the figures:

FIG. 1 is a view of a pipe wrench slipped onto a pipe,

FlG. 2 is a section taken along line 11-11 in FIG. 1, and

FIG. 3 is a view similar to FIG. 1 but showing the pipe wrench holding the pipe.

The pipe wrench has two pairs of rings 1, 2. The two outer rings 1 are interconnected by means of five bolts 6 and a bolt 4 so as to form a unit hereinafter referred to as ring unit 1-1 or the dog actuating ring. The bolts 6 are secured by means of locking washers 7. By means of five bolts and a bolt 10, all of which are secured by locking washers 7 as well, the two inner rings 2 are interconnected to form a ring unit hereinafter referred to as ring unit 2-2 or the holder ring. All of the bolts 4, 5, 6, have shoulders which hold the rings of the ring units in spaced relationship, and six dogs 3 of steel between the rings 2 are mounted on the bolts 5 and the bolt 10, respectively, so as to pivot thereon. The dogs 3 are cylindrical and besides the holes for the bolts 5 they have radial slots 3a through which the bolts 6 and 4 respectively extend. The two ring units 1-1 and 2-2 are turnable relative each other and the outer ring unit 1-1 is held in place relative to the ring unit 2-2 by means of the dogs 3.

A handle 8 has a bifurcated end portion 9 which is mounted so as to pivot on the bolt 10. Threaded guiding bolts 11 are fixed to the rings 1 of the outer ring unit 1-1 and they extend through elongated holes 12 in the end portion 9 of the handle.

When using the pipe wrench, one slips it onto a pipe 13, the handle being in the neutral position as shown in FIG. 1. When the handle 8 is being pivoted from its radial position of FIG. 1, the two ring units 1-1 and 2-turn relative to each other, the bolts 11 sliding in the holes 12. A turning of the dogs 3 on the bolts 5 and 10 respectively results from this turning so that the dogs grip the pipe as shown in FIG. 3. When the dogs 3 pivot, the bolts 6 and the bolt 4 slide in the slots 3a.

It is obvious that the wrench is reversible, i.e., that it can be used to grip both clockwise and counterclockwise as desired, depending on in which direction from the released middle position the handle 8 and thereby the jaws 3 are pivoted. The dogs 3 need not have circular section as shown but their gripping surfaces may have another arcuate form, and the number of dogs can of course be varied. Advantageously, the gripping surfaces of the dogs 3 are serrated so as to improve the gripping although this is not shown in the drawings.

The invention is not limited to the described embodiment but it may be varied in various ways within the scope of the claims.

What I claim is:

1. A pipe wrench comprising a holder ring having an opening through which a pipe or the like can be in serted, a number of dogs mounted in the holder ring so as to be pivotable about axes parallel to the axis of the opening, said dogs having arcuate pipe gripping surfaces, a dog actuating ring for positively pivoting all the dogs into engagement with the pipe when turned with respect to the holder ring, a lever pivotably mounted to one of said holder ring and dog actuating ring for pivoting about an axis parallel with the pivot axes of the dogs and engaging said other ring so as to turn the dog actuating ring with respect to the holder ring when the lever is moved into various angles with respect to the holder ring.

2. A wrench as claimed in claim 1 in which each dog has an arcuate gripping surface for engaging the pipe when the dog is pivoted in one direction from a released middle position and another arcuate gripping surface for engaging the pipe when the dog is pivoted in the other direction.

3. A wrench as claimed in claim 2 in which the dogs are cylindrical with substantially circular cross-section and excentrically mounted to pivot on bolts secured to the holder ring.

4. A wrench as claimed in claim 1 in which the holder ring comprises two concentric annular ring members interconnected by a number of bolts, and the dogs are pivotably mounted on said bolts between the ring members.

5. A wrench as claimed in claim 4 in which the dog actuating ring comprises two annular ring members interconnected by a number of bolts which extend through radial slots in the dogs.

6. A wrench as claimed in claim 1 wherein said lever is pivotally mounted to said dog actuating ring.

7. A wrench as claimed in claim 6 wherein said holder ring comprises two concentric annular ring members interconnected by a number of bolts, and wherein said lever includes a slot therein slidably engaged with at least one of the bolts.

8. A wrench as claimed in claim 4 in which the dogs have slots therein, the slots of said dogs slidably engaging respective bolts between the ring members. 

1. A pipe wrench comprising a holder ring having an opening through which a pipe or the like can be inserted, a number of dogs mounted in the holder ring so as to be pivotable about axes parallel to the axis of the opening, said dogs having arcuate pipe gripping surfaces, a dog actuating ring for positively pivoting all the dogs into engagement with the pipe when turned with respect to the holder ring, a lever pivotably mounted to one of said holder ring and dog actuating ring for pivoting about an axis parallel with the pivot axes of the dogs and engaging said other ring so as to turn the dog actuating ring with respect to the holder ring when the lever is moved into various angles with respect to the holder ring.
 2. A wrench as claimed in claim 1 in which each dog has an arcuate gripping surface for engaging the pipe when the dog is pivoted in one direction from a released middle position and another arcuate gripping surface for engaging the pipe when the dog is pivoted in the other direction.
 3. A wrench as claimed in claim 2 in which the dogs are cylindrical with substantially circular cross-section and excentrically mounted to pivot on bolts secured to the holder ring.
 4. A wrench as claimed in claim 1 in which the holder ring comprises two concentric annular ring members interconnected by a number of bolts, and the dogs are pivotably mounted on said bolts between the ring members.
 5. A wrench as claimed in claim 4 in which the dog actuating ring comprises two annular ring members interconnected by a number of bolts which extend through radial slots in the dogs.
 6. A wrench as claimed in claim 1 wherein said lever is pivotally mounted to said dog actuating ring.
 7. A wrench as claimed in claim 6 wherein said holder ring comprises two concentric annular ring members interconnected by a number of bolts, and wherein said lever includes a slot therein slideably engaged with at least one of the bolts.
 8. A wrench as claimed in claim 4 in which the dogs have slots therein, the slots of said dogs slideably engaging respective bolts between the ring members. 